In a charged particle radiation device, such as a scanning electron microscope, a transmission electron microscope, and a semiconductor inspection device, a sample is irradiated with charged particle radiation (an electron beam) generated in an ultra-high vacuum environment inside an electron optical lens tube, and a secondary electron, a reflection electron, or a transmission electron from the sample is detected, thereby acquiring an observation image of the sample. If the electron optical lens tube is vibrated, this will cause a change in a position of the electron beam irradiation to the sample, so that strain occurs to the observation image, and the edge of a pattern is seen as vibrating, or in the case of adding up the plurality of observation images, the edge of an image after addition will turn faint. For this reason, vibration of the electron optical lens tube will invite deterioration in picture quality of the observation image, and further, this will create a factor that will induce deterioration in resolution of the charged particle radiation device.
The semiconductor inspection device is a device for observing a defect occurring to a pattern of a semiconductor device subjected to exposure on a wafer, and classifying the defects by a defect type. Meanwhile, progress has lately been made in respect of miniaturization of the semiconductor device, increase in the diameter of a sample, and higher throughput. The electron optical lens tube is vibrated due to vibration of an ion pump that can be regarded as an added mass of the electron optical lens tube after stoppage of movement of a stage on which a sample is placed, thereby raising a possibility of causing deterioration in the picture quality. Accordingly, in order to implement further enhancement in throughput, it is necessary to quickly attenuate the natural vibration of the ion pump immediately after the stage is moved to an observation position.
Meanwhile, when attention is focused on a high-polymer vibration dampening material that has lately been introduced, a viscoelastic material high in dissipation factor and loss shear modulus has been developed.
In Patent Document 1 and Patent Document 2, respectively, a technology is disclosed for attenuating and blocking vibration propagating to an electron optical lens tube by use of a damper made of a viscoelastic material. In the case of the technology described in Patent Document 1, a damper is interposed between a yoke and a case, making up an ion pump, and between the case and a magnet, respectively. Accordingly, there exists a problem that the ion pump becomes complex in structure and baking becomes difficult to apply because a viscoelastic damper that will be cured by heating is disposed inside the ion pump. In the case of the technology described in Patent Document 2, a damper is interposed between a pedestal of a beam application device (a transmission electron microscope) and the floor. Accordingly, it is possible to block vibration propagated from the floor. However, there exists a problem that an advantageous effect of from the device itself, such as vibration occurring due to movement of a stage, cannot be expected.